Strand Test

you mix a smal portion of the stuff to do a strand test....most boxes tell how or call the 800 number for advice...most boxes I have used are 2 to 1 . 2 parts developer to 1 part color. I usually mix 2 t developer to 1t color in small plastic dish , then I test on an understrand and cover it with foil ( to protect other hair) to process checking often. Hope that helps. I did do a test strand with my most recent dark disaster....funny thing is the color looked pretty good on the test strand but NOT on the whole head